Cryptococcus tepidarius sp. nov., a thermotolerant yeast species isolated from a stream from a hot-spring area in Japan

Abstract

Anamorphic basidiomycetous yeast strains M9962T and M9963 were isolated from water samples collected from a small stream in Ohwakudani, Hakone, a hot-spring area in Japan. These belonged to a single species and were phylogenetically closely related to Bullera lagerstroemiae, although the ability to form ballistoconidia was not observed. Based on sequence analyses of the D1/D2 domain of the LSU rDNA and ITS regions and differences in G+C content, the name Cryptococcus tepidarius sp. nov. Takashima, Sugita, Toriumi et Nakase (Trichosporonales, Tremellomycetes, Basiomycota) is proposed for these isolates, with strain M9962 T (5SP-5 T 5JCM 11965 T 5CBS 9427 T ) as the type strain. The strains grew in YM broth at 47 6C and in YM broth with the pH adjusted to 1.5 by HCl, indicating that the species is thermotolerant and acid-tolerant.

Extremophilic yeasts: the toughest yeasts around?

“…Species with low temperature optima are more frequent among basidiomycetes (Robert et al, ). The highest growth temperature (47.7°C) among non‐human‐related basidiomycetous yeasts was recorded for Takashimella tepidaria (formerly Cryptococcus tepidarius ), which has been isolated from a hot‐spring area (Takashima, Sugita, Toriumi, & Nakase, ). The former genera Cryptococcus and Rhodotorula were the most commonly reported yeasts in early investigations carried out in cold habitats (reviewed by Buzzini et al, ).…”

“…Several yeasts have been isolated from naturally acid (pH 1–3) environments. Among them some acidophilic or acidotolerant species are able to grow at or below pH 2, namely Kazachstania exigua , Pichia kudriavzevii (former Candida krusei ), Pichia membranifaciens , S. cerevisiae and Zygosaccharomyces rouxii in the Ascomycota and R. glutinis , Slooffia tsugae , Takashimella formosensis and Takashimella tepidaria in the Basidiomycota (Nguyen et al, ; Pitt & Hocking, ; Péter et al, ; Raspor & Zupan, ; Takashima et al, ; Russo et al, ; Gadanho et al, ). Yeasts tolerating high pH values are mainly reported as members of the genera Barnettozyma , Cyberlindnera and Wickerhamomyces (Agno, ; Deak, ; Péter et al, ).…”

“…However, the taxonomic reorganization of both genera (Liu et al, 2016;Wang et al, 2015) has subsequently changed the use of yeasts names in more recent studies, so that members of genera Goffeauzyma, Naganishia, Papiliotrema, Solicoccozyma, Vishniacozyma and Phenoliferia, together with Cystobasidium, Rhodotorula, Dioszegia and Filobasidium appear among the most frequently found cold-adapted species (Buzzini, Turk, et al, 2017;Sannino et al, 2017). (Nguyen et al, 2001;Pitt & Hocking, 2009;Péter et al, 2017;Raspor & Zupan, 2006;Takashima et al, 2009;Russo et al, 2008;Gadanho et al, 2006). Yeasts tolerating high pH values are mainly reported as members of the genera Barnettozyma, Cyberlindnera and Wickerhamomyces (Agno, 1990;Deak, 2008;Péter et al, 2017 (Butinar et al, 2005).…”

Isolation of aquatic yeasts with the ability to neutralize acidic media, from an extremely acidic river near Japan's Kusatsu-Shirane Volcano

“…Yeast diversity has been extensively investigated (3). Several types of yeast have been isolated from these extreme acidic environments to date; e.g., Rhodotorula glutinis (4), Candida maltosa (5), and Cryptococcus tepidarius (6). In Saccharomyces cerevisiae, yeast genes involved in responses to acid stress have been studied (7)(8)(9).…”

Seasonal and plant‐dependent variations in diversity, abundance and stress tolerance of epiphytic yeasts in desert habitats

“…The ascomycetous yeast species Ogataea thermophila was reported to grow at 50°C and, therefore, has the highest growth temperature known to date (Shin et al ., ; Péter et al ., ); however, this strain has a unique 26S rRNA partial sequence that separates it from other ascomycetous yeasts. Takashima and colleagues () reported that Cr. tepidarius , isolated from a stream from a hot‐spring area in Japan, was able to grow at 47°C and, therefore, has the highest maximum growth temperature reported so far for basidiomycetous yeast.…”